1. Field of the Invention
The invention relates to a method for the production of phosphonic ester-modified organosilicon compounds by reaction of silanes containing phosphonic ester groups with reactive silicon compounds.
2. Description of the Related Art
Phosphonic ester-modified organosilicon compounds are of great economic interest for a multitude of sectors. For example, they may be used as lubricants of metals and textiles, flame-retardant additives, adhesion promoters, additives for cosmetics or laundry detergents, defoamers, release agents, damping fluids, heat transfer fluids, antistatic agents or for polishes and coatings.
Phosphorus-modified siloxanes are prepared generally by reaction of trialkyl phosphites with chloropropyl-modified siloxanes, as described, for example in Gallagher et al., J. Polym. Sci. Part A, Vol. 41, 48-59 (2003). Unfortunately, long reaction times and high temperatures are needed for this reaction, which leads to rearrangements in the product and thus to yield losses and also to unwanted by-products.
The reaction of trialkyl phosphites with chloromethyl-modified siloxanes as described in U.S. Pat. No. 2,768,193 or by Gallagher et al. proceeds significantly more quickly but has the disadvantage that the siloxanes thus produced are difficult to purify by distillation on account of their high boiling point. In addition, however, the progress of this reaction is slow, since the concentration of the reactive groups is greatly reduced by dilution with unreactive dimethylsiloxy units, resulting in reaction times in the region of several hours.